Method and Apparatus Providing Enhanced Radio Link Control Acknowledgment

1. A method to operate a radio link protocol receiver when receiving data blocks from a transmitter, comprising: receiving a data block; and making a determination in the receiver as to whether the size of a receive window is less than or equal to a bitmap size, where the bitmap size is the maximum size, in bits, of the bitmap to be reported in an acknowledgment message; if the determination is positive, then the reported bitmap covers the entire receive window, while if the determination is negative the reported bitmap covers only the beginning of the receive window and covers as many blocks as there are bits in the reported bitmap.

2. A method to operate a radio link protocol receiver when receiving data blocks from a transmitter, comprising: receiving a data block; and making a determination as to whether [V(R)−V(Q)] mod SNS≦bitmap size; if the determination is positive, then setting SSN=V(R); if the determination is negative, then setting SSN=[V(Q)+bitmap size] mod SNS, where V(S) is a send state variable that denotes a sequence number of a next in-sequence data block to be transmitted; SNS is a sequence number space that denotes a range [0; SNS-1] in which a block sequence number (BSN) takes its value, where each transmitted data block is assigned a BSN equal to V(S) at the time of transmission; V(Q) is a receive window state variable that denotes a lowest BSN not yet received (modulo SNS) and represents the start of a receive window; V(R) is a receive state variable that denotes the BSN which has a value one higher than the highest BSN yet received (modulo SNS); and SSN is a starting sequence number.

3. A method as in claim 2 , where if the determination is negative, the bitmap covers those data blocks having a BSN within the interval [V(Q), SSN-1].

4. A method as in claim 2 , further comprising setting a beginning of window bit to a one.

5. A radio link protocol receiver operable for receiving data blocks from a transmitter, comprising: means for receiving a data block; and coupled to said receiving means, receive control means for making a determination as to whether the size of a receive window is less than or equal to a bitmap size, where the bitmap size is the maximum size, in bits, of the bitmap to be reported in an acknowledgment message, where if the determination is positive, then the reported bitmap covers the entire receive window, while if the determination is negative the reported bitmap covers only the beginning of the receive window and covers as many blocks as there are bits in the reported bitmap.

6. A radio link protocol receiver operable for receiving data blocks from a transmitter, comprising: means for receiving a data block; and coupled to said receiving means, receive control means for making a determination as to whether [V(R)−V(Q)] mod SNS≦bitmap size and, if the determination is positive, for setting SSN=V(R), otherwise if the determination is negative, for setting SSN=[V(Q)+bitmap size] mod SNS, where V(S) is a send state variable that denotes a sequence number of a next in-sequence data block to be transmitted; SNS is a sequence number space that denotes a range [0; SNS-1] in which a block sequence number (BSN) takes its value, where each transmitted data block is assigned a BSN equal to V(S) at the time of transmission; V(Q) is a receive window state variable that denotes a lowest BSN not yet received (modulo SNS) and represents the start of a receive window; V(R) is a receive state variable that denotes the BSN which has a value one higher than the highest BSN yet received (modulo SNS); and SSN is a starting sequence number.

7. A receiver as in claim 6 , where if the determination is negative, the bitmap covers those data blocks having a BSN within the interval [V(Q), SSN-1].

8. A receiver as in claim 6 , where said receive control means further sets a beginning of window bit to a one.

9. A method to operate a radio link protocol receiver when receiving data blocks from a transmitter, comprising: receiving a data block; and making a determination at the receiver as to whether the size of a receive window is less than or equal to a bitmap size, where the bitmap size is the maximum size, in bits, of the bitmap to be reported in an acknowledgment message; and, if the determination is positive, the reported bitmap covers the entire receive window, while if the determination is negative, either a first partial bitmap covering an initial portion of the receive window is reported, or a next partial bitmap covering a portion other than the initial portion of the receive window is reported.

10. A method as in claim 9 , where determining whether a first partial bitmap or a next partial bitmap is sent comprises: determining if the previous acknowledgment message carried a partial bitmap that did not cover the highest BSN received at the time, and if the difference between: (a) the BSN that has a value one higher than the highest BSN yet received (V(R)), and (b) the highest BSN that was included in the bitmap when the previous acknowledgment message was transmitted (PBSN), is larger than a certain threshold value, PBSN_Threshold, then the next partial bitmap is sent provided that PBSN is still larger than the start of the receive window (V(Q)); otherwise the first partial bitmap is sent.

11. A method to operate a radio link protocol receiver when receiving data blocks from a transmitter, comprising: receiving a data block; and making a determination as to whether [V(R)−V(Q)] mod SNS≦bitmap size; if the determination is positive, then setting SSN=V(R); if the determination is negative, determining whether a first partial bitmap or a next partial bitmap is sent, where V(S) is a send state variable that denotes a sequence number of a next in-sequence data block to be transmitted; SNS is a sequence number space that denotes a range [0; SNS-1] in which a block sequence number (BSN) takes its value, where each transmitted data block is assigned a BSN equal to V(S) at the time of transmission; V(Q) is a receive window state variable that denotes a lowest BSN not yet received (modulo SNS) and represents the start of a receive window; V(R) is a receive state variable that denotes the BSN which has a value one higher than the highest BSN yet received (modulo SNS); and SSN is a starting sequence number.

12. A method as in claim 11 , where determining whether a first partial bitmap or a next partial bitmap is sent comprises: determining if [PBSN−V(Q)] mod SNS<WS and if [V(R)−(PBSN+PBSN_Threshold)] mod SNS<WS and, if the determination is positive, sending the next partial bitmap, otherwise sending the first partial bitmap, where PBSN_Threshold is a threshold value that identifies a limit for the difference between PBSN and V(R), beyond which a next partial bitmap is generated, and WS denotes window size.

13. A method as in claim 12 , where if the first partial bitmap is sent, then SSN=[V(Q)+bitmap size] mod SNS, and the bitmap covers those data blocks having a BSN within the interval [V(Q), SSN−1].

14. A method as in claim 12 , where the next partial bitmap characteristics are established by: determining if [V(R)−(PBSN+1)] mod SNS>bitmap size and, if the determination is positive, then SSN=[PBSN+1+bitmap size] mod SNS, and the bitmap covers those data blocks that have a BSN within the interval [PBSN+1, SSN-1]; and if the determination is negative, then SSN=V(R), and the bitmap covers a number of data blocks, determined by the bitmap size, that have a BSN smaller than the SSN.

15. A method as in claim 11 , further comprising setting a beginning of window bit to a zero if the next partial bitmap is sent, or to a one if the first partial bitmap is sent.

16. A radio link protocol receiver operable for receiving data blocks from a transmitter, comprising: means for receiving a data block; and coupled to said receiving means, receive control means for making a determination as to whether the size of a receive window is less than or equal to a bitmap size, where the bitmap size is the maximum size, in bits, of the bitmap to be reported in an acknowledgment message; and, if the determination is positive, the reported bitmap covers the entire receive window, while if the determination is negative, either a first partial bitmap covering an initial portion of the receive window is reported, or a next partial bitmap covering a portion other than the initial portion of the receive window is reported.

17. A receiver as in claim 16 , where said controller, when determining whether the first partial bitmap or the next partial bitmap is sent, makes a determination as to whether the previous acknowledgment message carried a partial bitmap that did not cover the highest BSN received at the time, and if the difference between: (a) the BSN that has a value one higher than the highest BSN yet received (V(R)), and (b) the highest BSN that was included in the bitmap when the previous acknowledgment message was transmitted (PBSN), is larger than a certain threshold value, PBSN_Threshold, then the next partial bitmap is sent provided that PBSN is still larger than the start of the receive window (V(Q)); otherwise the first partial bitmap is sent.

18. A radio link protocol receiver operable for receiving data blocks from a transmitter, comprising: means for receiving a data block; and coupled to said receiving means, receive control means for making a determination as to whether [V(R)−V(Q)] mod SNS≦bitmap size; if the determination is positive, for setting SSN=V(R); and if the determination is negative, for determining whether a first partial bitmap or a next partial bitmap is sent, where V(S) is a send state variable that denotes a sequence number of a next in-sequence data block to be transmitted; SNS is a sequence number space that denotes a range [0; SNS-1] in which a block sequence number (BSN) takes its value, where each transmitted data block is assigned a BSN equal to V(S) at the time of transmission; V(Q) is a receive window state variable that denotes a lowest BSN not yet received (modulo SNS) and represents the start of a receive window; V(R) is a receive state variable that denotes the BSN which has a value one higher than the highest BSN yet received (modulo SNS); and SSN is a starting sequence number.

19. A receiver as in claim 18 , where said receive control means determines whether a first partial bitmap or a next partial bitmap by determining if [PBSN−V(Q)] mod SNS< WS and if [V(R)−(PBSN+PBSN_Threshold)] mod SNS<WS and, if the determination is positive, said receive control means sends the next partial bitmap, otherwise said receive control means sends the first partial bitmap, where PBSN_Threshold is a threshold value that identifies a limit for the difference between PBSN and V(R), beyond which a next partial bitmap is generated, and WS denotes window size.

20. A receiver as in claim 19 , where if the first partial bitmap is sent, said receive control means sets SSN=[V(Q)+bitmap size] mod SNS, and the bitmap covers those data blocks having a BSN within the interval [V(Q), SSN−1].

21. A receiver as in claim 19 , said receive control means establishes the next partial bitmap characteristics by making a determination if [V(R)−(PBSN+1)] mod SNS>bitmap size and, if the determination is positive, said receive control means sets SSN=[PBSN+1+bitmap size] mod SNS, and the bitmap covers those data blocks that have a BSN within the interval [PBSN+1, SSN−1]; and if the determination is negative, said receive control means sets SSN=V(R), and the bitmap covers a number of data blocks, determined by the bitmap size, that have a BSN smaller than the SSN.

22. A receiver as in claim 18 , where said receive control means sets a beginning of window bit to a zero if the next partial bitmap is sent, or to a one if the first partial bitmap is sent.

23. A method to operate a radio link protocol mobile station when receiving data blocks from a base station, comprising: receiving a data block; and determining whether to transmit in an acknowledgment message a bitmap that reports an entire receive window or a bitmap that reports only a portion of the receive window based on a comparison made by the mobile station between a size of the receive window and a size of the bitmap.

24. A method as in claim 23 , where the entire receive window is reported if the size of the receive window is less than or equal to the size of the bitmap, and where the portion of the receive window is reported if the size of the receive window is greater than the size of the bitmap.

25. A method as in claim 23 , where the bitmap is transmitted as part of an acknowledgment message that always includes a channel measurement report.

26. A mobile station comprising a receiver for receiving data blocks from a base station and a controller for determining whether to transmit in an acknowledgment message a bitmap that reports an entire receive window or a bitmap that reports only a portion of the receive window based on a comparison made by the mobile station between a size of the receive window and a size of the bitmap, where the size of the bitmap is the maximum size, in bits, of the bitmap to be reported in the acknowledgment message.

27. A mobile station as in claim 26 , where said controller reports the entire receive window if the size of the receive window is less than or equal to the size of the bitmap, and reports the portion of the receive window if the size of the receive window is greater than the size of the bitmap.

28. A mobile station as in claim 26 , where the bitmap is transmitted as part of an acknowledgment message that always includes a channel measurement report.